Company News: Twitter, Yahoo!, Berkshire Hathaway

Twitter and Yahoo’s Flickr have unveiled new tools to adjust the color, size, and style of photos uploaded to mobile apps in a direct challenge to Facebook’s Instagram. The new photo tools came a week after Instagram—in a bid to generate more revenue by driving traffic to its own website—made it harder for users to embed photos in Tweets. Both Twitter and Flickr worked with the software maker Aviary to develop the picture tools. In other mobile upgrades, Twitter now allows users to add video and audio to posts, and Yahoo upgraded its e-mail service to be faster and easier to navigate on the go.

Warren Buffett’s Berkshire Hathaway cleared the way to buy back more shares, signaling that the billionaire chairman views its stock as undervalued. Berkshire bought $1.2 billion in shares from the estate of a longtime shareholder, and on Dec. 12 increased by 9 percent how much it is willing to pay for other shares. It will now pay up to 120 percent of the per share price of the company’s assets minus liabilities. The buybacks come as Buffett looks for large acquisitions and other ways to deploy Berkshire’s $47.8 billion cash hoard.